Dishwasher and spray system therefor

ABSTRACT

A dishwasher having lower, center and upper article receiving racks and a spray mechanism for distributing washing liquid toward all of the racks. The spray mechanism comprises a rotatable hub, a first spray arm on the hub under the lower rack for directing washing liquid theretoward, a second spray arm below the center rack for directing washing liquid theretoward and a spray tower telescopingly received in the hub for extensible upward movement toward the upper rack for distributing washing liquid theretoward. A seal is provided between the hub and the spray tower for reducing liquid therebetween. The spray tower is balanced to prevent cocking thereof relative to the hub thereby preventing a seal failure between the spray tower and the hub.

Cushing eta].

DISHWASHER AND SPRAY SYSTEM THEREFOR lnventors: Donald S. Cushing; Thomas E.

Jenkins, both of Louisville, Ky.

Assignee: General Electric Company,

Louisville, Ky.

Filed: Jan. 2, 1973 Appl. No.: 320,614

US. Cl 134/144, 134/176, 239/251 Int. Cl 1308b 3/02 Field of Search 134/144, 176, 179;

11/1966 Jordan et a1 12/1966 Braden et a1. 134/176 X Primary Examiner-Robert L. Bleutge Attorney, Agent, or Firm-Francis H. Boos 57 ABSTRACT A dishwasher having lower, center and upper article receiving racks and a spray mechanism for distributing washing liquid toward all of the racks. The spray mechanism comprises a rotatable hub, a first spray arm on the hub under the lower rack for directing washing liquid theretoward, a second spray arm below the center rack for directing washing liquid theretoward and a spray tower telescopingly received in the hub for extensible upward movement toward the upper rack for distributing washing liquid theretoward. A seal is provided between the hub and the spray tower for reducing liquid therebetween. The spray tower is balanced to prevent cocking thereof relative to the hub thereby preventing a seal failure be-- tween the spray tower and the hub.

11 Claims, 3 Drawing Figures PATENIEBUCT 1 511174 SWEET 1 0f 2 FIG. I

DISHWASHER AND SPRAY SYSTEM THEREFOR This invention relates generally to dishwashers and more particularly to spray devices therefor. One of the techniques known in the prior art to deliver washing liquid to an upper rack is the provision of an extensible spray tower such as shown in US. Pat. No. 3,077,200. In devices of this type, a seal is provided between the extensible and stationary members of the tower to reduce liquid leakage therebetween and thereby promote distribution efficiency.

One problem that can occur in devices of this type is maintaining the seal between the stationary and movable parts of the spray tower. If a laterally directed spray opening is provided on the spray tower, it has been found that the reaction force created by liquid emitting from the opening creates a moment which can tilt the extensible tower sufficiently to break the seal between the extensible and stationary portions of the spray tower. In this invention, this difficulty is obviated by providing a plurality of oppositely laterally directed spray openings. The size of the openings, the angle of discharge of the openings and the distance from the openings to the sealing joint are selected such that the moment imposed on the extensible tower is insufficient to break the seal.

Another aspect of this invention resides in the incorporation of an extensible spray tower in a Zshaped spray arm having spray openings at different levels.

It is an object of this invention to provide a dishwasher having an extensible spray tower and means for at least partially laterally balancing the spray tower.

Another object of this invention is to provide a spray tower for a dishwasher including upper and lower laterally directed spray openings.

One aspect of the invention comprises a dishwasher having a spray conduit therein mounted for generally vertical telescoping movement between upper spray and lower inoperative positions and having at least one laterally directed spray opening creating a reaction force tending to cant the conduit and thereby break a seal between the conduit and the spray hub, and means operative in the upper conduit position creating a moment on the conduit for restoring the same to the sealed position.

Other aspects, features and advantages of the invention will become more fully apparent as the description proceeds.

IN THE DRAWING FIG. 1 is a vertical cross sectional view of a dishwasher incorporating the principles of this invention;

FIG. 2 is a partial broken view of the spray means of FIG. 1 illustrating the same in an inoperative position; and

FIG. 3 is an enlarged vertical cross sectional view of the spray conduit in the upper spray position.

Referring to FIG. 1, there is illustrated a dishwasher comprising as major components a cabinet 12 having therein a tub 14 providing a wash chamber 16,

lower, center and upper racks 18, 20, 22 respectively, a pump-motor 24 and spray means 26 for delivering washing liquid toward the racks 18, 20, 22.

The tub 14 comprises side walls 28, a top 30, a back 32, and a bottom 34 thus providing the wash chamber 16. The wash chamber 16 includes a side opening 36 V which is closed by a conventional door 38 pivoted adjacent the lower end thereof.

The lower rack 18 is preferably adapted to receive pots and pans and accordingly provides a flat bottom 40. The lower rack 18 also provides a conventional passage 42 extending from the rear thereof forwardly of the spray means 26. The rack 18 is accordingly free to move outwardly of the wash chamber 16 as allowed by a plurality of wheels 44 which are supported by ledges 46 on the tub side walls 28 and the inner surface of the door 38 as is conventioal. The lower rack 18 includes runners 48 on each side thereof to provide a support for the center rack 20 during outward movement from the washing position shown in FIG. 1.

The center rack 20 comprises a wire latticework having front wheels 50 thereon which engage the runners 48 during outward movement of the center rack 20 toward a dish loading position. A plurality of rear wheels 52 typically remain in supporting engagement with a ledge 54 carried by the tub side walls 28. An intermediate set of wheels 56 are provided for engaging a ramp 58 afforded by the ledge 54 for elevating the forward end of the center rack 20 as it moves toward the washing position of FIG. 1. With the rack 20 in the washing position, the front wheels 50 are elevated out of load supporting engagement with the lower rack 18 thereby enabling independent movement of the rack 18 between washing and loading positions respectively in and at least partially out of the chamber 16. The center rack 20 includes a passage 60 extending from the rear thereof forwardly past the spray means 26 to allow movement of the rack 20 therepast.

The upper rack 22 also comprises a non-corrosive wire latticework carrying suitable wheels 62 received in a conventional guide and slide device 64 thereby mounting the rack 22 for movement between washing and loading positions.

The tub bottom 34 separates the wash chamber 16 from a pump-motor compartment 66. The tub bottom 34 provides an opening therethrough of sufficient dimension to pass the pump-motor 24 vertically therethrough. Accordingly, the pump-motor compartment 66 need not be of sufficient height to remove the pumpmotor 24 horizontally through the front of the dishwasher 10. Mounting the pump-motor 24 to the tub bottom 34 is support means 68 comprising an annular seal 70, an annular strap 72, a circular clamp 74 of wedge shaped cross section and suitable supports (not shown) carried by the strap 92 for supporting the motor and pump ends of the pump-motor 24.

Captivated by the support means 68 is a flexible boot 76. The inner periphery of the boot 76 is sealed about the pump outlet 78 by a suitable threaded connection 80 as shown in FIG. 2. The boot 76 provides a passage 82 leading from the tub bottom 34 to the pump inlet.

Overlying the boot 76 is a rigid metallic shell 84. The lower edge 86 of the shell 84 is spaced from the tub bottom 34 by suitable shims and fasteners 88 allowing flow of washing liquid into the passage 82 for delivery to the pump inlet.

As shown best in FIG. 2, a collar 88 is supported by the rigid shell 84 with a seal 90 being provided between the pump outlet 78 and the collar 88. The seal 90 is conveniently captivated to the pump outlet 78 by the threaded connection 80. The seal 90 may either be expansible into the sealing engagement with the collar 88 or may be secured thereto in any convenient manner.

The spray means 26 comprises a hub or stand pipe 92 mounted for rotation about a vertical axis on the collar 88, a first spray arm 94 under the lower rack 18, a second spray arm 96 between the lower and center racks 18, and a spray tower or conduit 98. The hub 92 includes a collar 100 surrounding the mounting collar 88 with suitable bearing means therebetween. Threaded on the collar 100 is a fitting 102 having a passage 104 therein for delivering pressurized washing liquid to the first spray arm 94. The spray arm 94 includes a multiplicity of upwardly directed spray opening 106 and a suitable reaction nozzle 108 for rotating the spray arm 94 and consequently the hub 92 about the axis thereof.

Threaded into the top of the fitting 102 is a tapered conduit 110 which captivates the spray arm 94 against the fitting 104. The second spray arm 96 is rigid with the conduit 110 and may comprise a conventional spray arm having upwardly directed openins therein or may include an imperforate section 1 12 having a perforate star wheel 114 rotatably mounted thereon. The star wheel 114 may comprise a plurality of upwardly directed spray openings therein spaced at different distances from the axis of rotation. An indexing roller 116 may be provided on anysuitable location in the path of movement of the spray arm 96, such as on an abutment 118, for indexing the star wheel 114.

It will be seen that the spray arms 96, 98 each comprise one end rigid with the conduit 110 and another end spaced from the axis of rotation. Since the spray arms 94, 96 have approximately the same moment of inertia, it will be apparent that the hub 92 and thespray arms 94, 96 are substantially balanced about the axis of rotation. It will be apparent that the material required to fabricate the spray arms 94, 96 is substantially the same as that required to fabricate a conventional spray arm in which the center is rigid with the rotatable hub.

The spray tower 98 extends through an opening 120 in the hub 92 and is mounted for generally vertical movement between an upper spray position (FIG. 1) and a lower inoperative position (FIG. 2). An abutment 122 is conveniently provided on the fitting 102 to support the spray tower 98 in the lower inoperative position.

The spray tower 98 includes a conduit 124 having an upper spray opening 126 and a lower spray opening 128. Integral with the lower end of the conduit 124 is an enlarged end 130 which is supported by the abutment 122 in the inoperative position of FIG. 2 and constrained by a hub top wall 132 in the upper spray position of FIG. 3.

The general operation of the spray tower 98 will be apparent to those skilled in the art and is disclosed in greater detail in U.S. Pat. No. 3,077,200. As pressurized washing liquid is delivered by the pump-motor 24 to the hub 92, the spray tower 98 is elevated with respect to the hub 92 until the enlarged end 130 abuts the hub top wall 132. A seal is formed by a pair of mating surfaces 134, 136 on the spray tower 98 and hub 92 respectively. Leakage of pressurized washing liquid through the opening 120 is accordingly minimized so that substantially the entire output from the pumpmotor 24 is distributed between the spray arms 94, 96 and the spray tower 98 as will be apparent to those skilled in the art. When the pump-motor 24 shuts off, washing liquid in the spray means 26 tends to drain out of the spray openings 106. Accordingly, the spray tower 98 falls by gravity from the position illustrated in FIGS. 1 and 3 toward the position shown in FIG. 2.

The spray means 26 of this invention is illustrated in a three rack dishwasher in which the effective height of the wash chamber 16 has been increased. Because of this, the tower 98 necessarily must undergo greater vertical telescoping movement and is accordingly longer than comparable towers in the prior art. This has accentuated a problem which has apparently existed in prior art spray towers. This problem relates to the maintenance of a seal between the surfaces 134, 136 as will become more apparent hereinafter.

As shown best in FIG. 3, the upper spray opening 126 defines a generally downwardly directed spray path 138 while the lower spray opening 128 defines a generally upwardly directed spray path 140. In the prior art, spray towers are typically provided with a single laterally directed spray opening comparable to the opening 126. Washing liquid emitting from the opening 126 creates a reaction force B which resolves into vertical and horizontal components B, B respectively. It will be apparent that the horizontal component B acts through a moment arm Y, plus Y, to cant or pivot the spray tower 98 about a fulcrum 142 thereby opening a gap 144 between the sealing surfaces 134, 136. It will be apparent that the creation of the gap 144 will deleteriously affect operation of the spray means 26. Upon analysis, it will be apparent that there is an inherent moment created on the spray tower 98 tending to restore the surfaces 134, 136 to a sealing position. This restoring moment is a summation of the forces P, A,, P A P A, acting through the moment arm C,. These forces generated on the interior of the spray tower 98 are the product of the pressures at the various levels therein and the areas exposed thereto. The moment arm C, is the distance from the center line 146 of the spray tower to the fulcrum 142.

In order to maintain the surfaces 134, 136 in the sealed position, the restoring moment must equal or ex-' ceed the net seal opening moment of the reaction force B, i.e., (B (Y, plus Y minus (B,,) (C,). It will be appreciated that conventional spray towers will not generate a sufficient restoring moment because of the increased length of the moment arm Y, plus Y After discovering the problem and analyzing the hydraulics of the spray tower 98, several approaches are within the realm of possibility including adjusting the size of the opening 126 and the liquid discharging therethrough to reduce the magnitude of the reaction force B, making the opening 126 more downwardly directed in order to decrease the horizontal reaction component B, and increase the vertical component B,,, and increase the size of the hub 92 to increase the restoring moment arm C,. Each of these approaches has a substantial disadvantage. It is, of course, desirable to spray the greatest possible quantity of liquid through the opening 126 at the greatest possible pressure to achieve maximum washing efficiency. Making the opening 126 more downwardly directed has obvious limitations since the spray path 138 must reach articles in the far reaches of the upper rack 22. Enlarging the hub 92 has apparent limitations.

In order to increase the restoring moment, avoid the disadvantages of the approaches heretofore suggested and create additional advantages, the lower spray opening 128 is provided. Washing liquid emitting from the spray opening 128 creates a reaction force D which may be resolved into horizontal and vertical components D,, D,,. The moment produced by the horizontal reaction component D acting through its moment arm Y supplements the moment restoring the surfaces 134, 136 to the sealed position. The moment produced by the vertical reaction component D acting through its moment arm C acts to increase the moment tending to break the seal between the surfaces 134, 136. It will be apparent that it is a relatively simple matter to assure that the net reaction moment produced by the spray opening 128 adds to the restoring moment by selecting the vertical position of the opening 128 on the spray tower 98 thereby controlling the length of the moment arm Y and by selecting the direction of the spray path 140 thereby controlling the ratio between the horizontal and vertical reaction components D D As is apparent from FIG. 1, the moment arm Y is substantially less than the moment arm Y plus Y Accordingly, if the horizontal reaction components B D were equal, the effect of the seal opening movement produced by the reaction component B, would predominate. Since it is desirable that the moments produced by the reaction forces B, D be more nearly equal, the reaction component D is desirably greater than the reaction component B,. This may be accomplished either by making the spray opening 128 horizontally directed or by increasing the reaction force D. The former is less desirable since the spray path 140 should intersect the upper rack 22. Accordingly, the reaction force D is increased by making the opening 128 larger than the opening 126.

In order to assure that the spray tower 98 does not pivot about the fulcrum 142, the net seal opening moment of the reaction force B less the net seal closing moment of the reaction force D must be equal to or less than the restoring moment which is the summation of the forces P A,, P A P A acting through the moment arm C,.

It will be apparent that the moment produced by the reaction force D can be too great thereby tending to pivot the spray tower 98 about a fulcrum 148 thereby tending to create a gap 150 on the opposite side of the hub end 130. Analysis will reveal that the reaction force D tends to pivot the spray tower 98 about the fulcrum 148 thereby opening the gap 150 while the reaction force B tends to close the gap 150. Accordingly, in order to prevent the gap 150 from occurring, the net seal opening moment about the fulcrum 148 produced by the reaction forces B, D should be equal to or less than the restoring moment.

The provision of the lower spray opening 128 has an advantage in addition to maintaining the seal between the surfaces 134, 136. As shown best in FIG. 1, the upper spray opening 126 resides about the upper rack 22 when the spray tower 98 is in the upper spray position. Accordingly, washing liquid in the path 138 acts to clean upwardly facing surfaces of articles in the rack 22. The lower spray opening 128 is illustrated below the upper rack 22 such that washing liquid in the path 140 acts to clean downwardly directed surfaces of articles in the rack 22. It will accordingly be seen that cleaning the downwardly directed surfaces of articles in the rack 22 is independent of the efficiency of the spray arm 96 and independently of masking of the spray path thereof.

Although the spray tower 98 is illustrated as extending above the upper rack 22, it may be desirable to terminate the tower 98 below the upper rack 22. In this circumstance, suitable means (not shown) are provided adjacent the tub top 30 for spraying downwardly on the upper rack 22 for cleaning the upwardly facing surfaces of articles therein. Although the spray tower 98 is not as long in this situation, the tower 98 is subject to tilting thereby breaking the seal between the hub 92 and the tower 98. Terminating the tower 98 below the upper rack 22 provides an additional advantage since the spray path 138 from the upper spray opening 126 projects toward the center rack 20. Thus there is provided an efficient downwardly directed spray on the center rack 20 which is not masked.

I claim:

1. A dishwasher comprising a .tub providing a wash chamber having an opening therein; a door for closing the opening; racks in the chamber; means mounting the racks for movement between washing and loading positions respectively in and at least partially out of the wash chamber; and spray means for distributing washing liquid toward the racks, the spray means comprising a stand pipe, a spray conduit having at least one upper and at least one lower spray opening providing generally oppositely directed spray paths, said lower spray opening being preselectively located in said spray conduit such that when washing liquid passes therethrough a restoring moment is produced on said spray conduit to counteract, at least in part, a similar moment produced when washing liquid passes through said upper spray opening; means mounting the spray conduit for generally vertical telescoping movement relative to the stand pipe between upper spray and lower inoperative positions in response to the delivery of pressurized washing liquid to the conduit, and seal means operative in the upper conduit position between the conduit and the stand pipe for reducing liquid leakage therebetween.

2. The dishwasher of claim 1 wherein the upper spray opening is downwardly and laterally directed.

3. The dishwasher of claim 2 wherein the lower spray opening is upwardly and laterally directed.

4. The dishwasher of claim 2 wherein the lower spray opening is larger than the upper spray opening.

5. The dishwasher of claim 2 wherein one of the racks resides between the spray openings in the upper conduit position.

6. A dishwasher comprising a tub providing a wash chamber having an opening therein; a door for closing the opening; racks in the chamber; means mounting the racks for movement between washing and loading positions respectively in and at least partially out of the wash chamber; and spray means for distributing washing liquid toward the racks, the spray means comprising a stand pipe, a spray conduit and means mounting the spray conduit for generally vertical telescoping movement relative to the stand pipe between upper spray and lower inoperative positions in response to the delivery of pressurized washing liquid to the conduit, seal means operative in a sealed position at the upper conduit position for sealing between the conduit and the stand pipe, means operative in the upper conduit posi tion creating a moment on the conduit for restoring the same to the sealed position, the restoring moment means consisting essentially of downwardly directed surfaces on the conduit exposed to the pressure of washing liquid, the spray conduit having at least one laterally directed spray opening therein creating a reaction moment tending to cant the conduit relative to the stand pipe in the upper conduit position and thereby move the conduit from the sealed position toward an unsealed position, and reaction means operative in the upper conduit position creating a moment on the conduit for supplementing the restoring moment.

7. The dishwasher of claim 6 wherein the spray conduit provides a second spray opening therein directed generally oppositely to the first mentioned spray opening, the second spray opening comprising the reaction means.

8. The dishwasher of claim 6 wherein the reaction moment of the spray opening and the moment of the reaction means is equal to or less than the restoring moment.

9. A dishwasher comprising a tub providing a wash chamber having an opening therein; a door for closing the opening; lower, center and upper racks in the chamber; means mounting the racks for movement between washing and loading positions respectively in and at least partially out of the wash chamber; and

spray means for distributing washing liquid toward all of the racks comprising a hub and means mounting the hub for rotation about a vertical axis, a first spray arm having one end thereof rigid with the hub below the lower rack and having the other end thereof spaced from the hub, a second spray arm having one end thereof rigid with the hub between the center and lower racks and having the other end thereof spaced from the hub in a direction generally opposite to the other end of the first spray arm, the hub, first and second spray arms defining a generally Z-shaped strucutre, a spray conduit having at least one spray opening therein for spraying toward the upper rack, and means mounting the conduit for generally vertical telescoping movement in and out of the hub in response to the delivery of pressurized washing liquid to the hub.

10. The dishwasher of claim 9 wherein the spray conduit has vertically spaced upper and lower spray openings therein straddling the upper rack in the upper conduit position.

11. The dishwasher of claim 10 wherein the upper spray opening is downwardly and laterally directed toward the upper rack and the lower opening is upwardly and laterally directed toward the upper rack. 

1. A dishwasher comprising a tub providing a wash chamber having an opening therein; a door for closing the opening; racks in the chamber; means mounting the racks for movement between washing and loading positions respectively in and at least partially out of the wash chamber; and spray means for distributing washing liquid toward the racks, the spray means comprising a stand pipe, a spray conduit having at least one upper and at least one lower spray opening providing generally oppositely directed sprAy paths, said lower spray opening being preselectively located in said spray conduit such that when washing liquid passes therethrough a restoring moment is produced on said spray conduit to counteract, at least in part, a similar moment produced when washing liquid passes through said upper spray opening; means mounting the spray conduit for generally vertical telescoping movement relative to the stand pipe between upper spray and lower inoperative positions in response to the delivery of pressurized washing liquid to the conduit, and seal means operative in the upper conduit position between the conduit and the stand pipe for reducing liquid leakage therebetween.
 2. The dishwasher of claim 1 wherein the upper spray opening is downwardly and laterally directed.
 3. The dishwasher of claim 2 wherein the lower spray opening is upwardly and laterally directed.
 4. The dishwasher of claim 2 wherein the lower spray opening is larger than the upper spray opening.
 5. The dishwasher of claim 2 wherein one of the racks resides between the spray openings in the upper conduit position.
 6. A dishwasher comprising a tub providing a wash chamber having an opening therein; a door for closing the opening; racks in the chamber; means mounting the racks for movement between washing and loading positions respectively in and at least partially out of the wash chamber; and spray means for distributing washing liquid toward the racks, the spray means comprising a stand pipe, a spray conduit and means mounting the spray conduit for generally vertical telescoping movement relative to the stand pipe between upper spray and lower inoperative positions in response to the delivery of pressurized washing liquid to the conduit, seal means operative in a sealed position at the upper conduit position for sealing between the conduit and the stand pipe, means operative in the upper conduit position creating a moment on the conduit for restoring the same to the sealed position, the restoring moment means consisting essentially of downwardly directed surfaces on the conduit exposed to the pressure of washing liquid, the spray conduit having at least one laterally directed spray opening therein creating a reaction moment tending to cant the conduit relative to the stand pipe in the upper conduit position and thereby move the conduit from the sealed position toward an unsealed position, and reaction means operative in the upper conduit position creating a moment on the conduit for supplementing the restoring moment.
 7. The dishwasher of claim 6 wherein the spray conduit provides a second spray opening therein directed generally oppositely to the first mentioned spray opening, the second spray opening comprising the reaction means.
 8. The dishwasher of claim 6 wherein the reaction moment of the spray opening and the moment of the reaction means is equal to or less than the restoring moment.
 9. A dishwasher comprising a tub providing a wash chamber having an opening therein; a door for closing the opening; lower, center and upper racks in the chamber; means mounting the racks for movement between washing and loading positions respectively in and at least partially out of the wash chamber; and spray means for distributing washing liquid toward all of the racks comprising a hub and means mounting the hub for rotation about a vertical axis, a first spray arm having one end thereof rigid with the hub below the lower rack and having the other end thereof spaced from the hub, a second spray arm having one end thereof rigid with the hub between the center and lower racks and having the other end thereof spaced from the hub in a direction generally opposite to the other end of the first spray arm, the hub, first and second spray arms defining a generally Z-shaped strucutre, a spray conduit having at least one spray opening therein for spraying toward the upper rack, and means mounting the conduit for generally vertical telescoping movement in and out of the hub in response to the delivery of presSurized washing liquid to the hub.
 10. The dishwasher of claim 9 wherein the spray conduit has vertically spaced upper and lower spray openings therein straddling the upper rack in the upper conduit position.
 11. The dishwasher of claim 10 wherein the upper spray opening is downwardly and laterally directed toward the upper rack and the lower opening is upwardly and laterally directed toward the upper rack. 